function show(polygons, cities,name_cities,population_cities) {
    var mapDiv = document.getElementById('map');
    var bounds = new google.maps.LatLngBounds();
    var options = {
        center: new google.maps.LatLng(10.0341527, 105.7564947, 13),
        zoom: 8,
        mapTypeId: google.maps.MapTypeId.ROADMAP,
        mapTypeControl: true,
        mapTypeControlOptions: {
            style: google.maps.MapTypeControlStyle.DROPDOWN_MENU,
            position: google.maps.ControlPosition.BOTTOM_RIGHT
        },
        scaleControl: true
    };
    var map = new google.maps.Map(mapDiv, options);
    //Gọi các phương thức
    setPolygons();
    setCities();
    //Định nghĩa các phương thức
    function setPolygons() {
        for (var i = 0; i < polygons.length; i++) {
            polygons[i].setMap(map);
        }
    }
    
    function setCities()
    {
        var inforwindow;
        for (var i = 0; i < cities.length; i++) {
            bounds.extend(cities[i]);
            var pointMarker = new google.maps.Marker({
                position: cities[i],
                map: map,
                icon: "icons/marker_green.png"
            });
            (function (i, pointMarker) {
                
                google.maps.event.addListener(pointMarker, 'click', function () {
                    if (!inforwindow)
                        inforwindow = new google.maps.InfoWindow();
                    var name = name_cities[i];
                    var pol = population_cities[i];
                    inforwindow.setContent(name+"<br/>Mật độ dân số: "+pol+" người /km vuông");
                    inforwindow.open(map, pointMarker);
                });
            })(i, pointMarker);
        }
        map.fitBounds(bounds);
    }
}